This invention relates to electrical connections of the type used to couple and uncouple the electrical system of a tractor unit to a trailer.
The electrical connection between truck tractor units and trailers for such services as lights, brake lights, indicators is a standardised 7 pin ISO 1185 (24N) connector and other auxiliary equipment may be connected through a 7 pin ISO 3731 (24S) connector. Most trailers are equipped with both types of connector and additionally some trailers may be equipped with an ISO 7638 connector for the ABS system on trailer if fitted. As an alternative to the latter connector the ABS system can be activated through a stop light pins of the ISO 1185 connector. Recently a new ISO 12098 15 pin connector has been introduced to combine all the features of the other three connectors.
With the variety in Make, type and age of trailer the only standard connector which all trailers have is the ISO 1185 connector and even when some trailers have other additional connectors some drivers only make the minima electrical connections between the tractor unit and trailer to operate the lights and indicator, i.e using the ISO 1185 connector, and therefor the trailer has only intermittent electrical power only when the brakes, lights, or indicators are operated and connected through the ISO 1185 connector.
It is becoming desirable to install trailer tracking and/or data logging systems in vehicle trailers to report on the trailer locations and/or status e.g coupled or uncoupled to the motor vehicle. An intermittent power supply to a trailer makes it impossible to automatically detect whether the trailer is coupled or uncoupled to a tractor unit by sensing the power supply to the trailer.
The object of the present invention is to sense the coupled/uncoupled status of a vehicle trailer independently of the power supply to the trailer, and preferably by using the standard power connectors.
According to the present invention there is provided a vehicle trailer male electrical connector having an array of electrical connector pins for interconnecting electrical power between a vehicle trailer and tractor unit and which includes a switch in one of an open or closed condition and which is operated through one of said pins to change the condition of the switch by axial displacement of said one pin on engagement with a co-operating female connector on the tractor unit.
Said one connector pin may be also used as a power connector, but is preferably not utilised as a power connector. The pins may be part of any ISO standard connector e.g. ISO 1185, ISO 3731, ISO 7638 or ISO 12098.
The pin at its inner end extends through the body of the connector to operate the switch when the pin is displaced.
The pin may include a coaxial extension which seats against, or is proximate to, the switch which may be a proximity switch, or is preferably a push button switch having an internal spring biasing the switch to a open condition.
Also according to the invention there is provided a method of activating a trailer tracking and/or data logging system sensing coupling and uncoupling between the tractor unit and a trailer in which method a switch, in an open or closed condition, is located on one half of a power connector which is used for electrically connecting the trailer to the tractor unit, and the condition of the switch is automatically changed when the two halves of the power connector are interconnected, the change in condition of the switch being sensed by said system.